On 29/05/2021 13:24, David wrote:
I need to cut a 30 mm hole in some 0.8 mm aluminium.

I have various hole cutting devices such as Forstner bits but they are for
wood.

Is there anything clever for cutting holes in metal sheets?

Any metal cutting hole-saw should be fine. Use oil to stop the aluminium
balling though with just 0.8mm it's only marginally necessary.